Long-Time Stability of Catalytic Coatings on the Basis of Nanoporous TiO 2 under the Influence of Corona Discharge Plasm
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Long-Time Stability of Catalytic Coatings on the Basis of Nanoporous TiO2 under the Influence of Corona Discharge Plasma in Air Sergey Karabanov, Dmitry Suvorov, Gennady Gololobov, Maria Klyagina, Vladimir Vasilyev, Nikolay Vereshchagin, Evgeny Slivkin Ryazan State Radio Engineering University 59/1 Gagarina St., Ryazan 390005, Russia ABSTRACT The present paper contains results of the experimental researches of structure properties of the catalytic coating based on the nanoporous TiO2 film affected by corona-discharge plasma in air atmosphere under atmospheric pressure in the test system of needle-plane electrodes. Coating of the plate electrode was found to influence insignificantly on the discharge currentvoltage characteristic, however if there is a coating on the plane electrode surface, an offset is observed towards lower currents under constant voltage at the gap. Obtained data on the surface morphology change shows that under negative corona erosion of the nanoporous TiO2 coating surface is practically absent and under positive corona, decrease of the coating thickness is observed. INTRODUCTION Coatings based on the nanoporous TiO2 film have high catalytic activities in relation to VOCs. It is known that VOCs decomposition rate in the air increases under simultaneous usage of catalytic coatings and corona discharge plasma. The main reason of combined purification high efficiency is supposed to be actions of the corona discharge firstly providing VOCs decomposition due to plasma-chemical reactions mainly with ozone formed in the area of discharge and secondly – charging and transporting large particles and aerosols of the impurity to the surface having TiO2 coating with photocatalytic properties. Besides, generation of the UV-radiation necessary for photocatalytic VOCs decomposition is ensured by the corona discharge itself. Issues for efficiency increase of the simultaneous usage of corona-discharge plasma and photocatalytic coatings based on the nanoporous TiO2 film is a subject of intense research [1-5]. But long-time stability of catalytic coatings based on the nanoporous TiO2 film affected by the corona-discharge plasma in the air has not been enough studied that limits possibility of practical application in the system of air cleaning. The present paper is dedicated to the experimental research of long- time stability of parameters of catalytic coatings based on the nanoporous TiO2 film under impact of the corona discharge plasma in air under atmospheric pressure. EXPERIMENTAL PROCEDURE Test bench was developed for the experimental research of stability of catalytic coatings based on the nanoporous TiO2 film. This test bench contains a bipolar stabilizable and adjustable high-voltage source, kilovoltmeter, microammeter, electrode system. Classical and well studied “needle-plane” system was chosen as an electrode system. Radius of the needle rounding – 15 μm, diameter – 0.3 mm, length – 35 mm. Distance between the needlepoint and plane electrode is 5-15 mm. The plane electrode is a titanic plane having dim
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